This invention relates generally to apparatus for decorating containers and, more particularly, is directed to apparatus for intermittently supplying rows of stacked cups to a feeding assembly of such a container decorating apparatus.
In general, a variety of machines for applying decorative finishes to plastic frusto-conical cups are known. Such machines include an intermittently rotatable mandrel wheel having a plurality of spaced, radially directed mandrels located on the periphery of the mandrel wheel for holding the cups thereon. Each cup is received on a corresponding mandrel at the loading station. Such machines conventionally include a feeding assembly which receives a stack of cups and feeds the cups one at a time onto each mandrel, as the mandrel wheel is rotated. The mandrels are then intermittently rotated with the mandrel wheel to a pre-treatment station, a printing station, a cure station and finally to an unloading station at which the cup thereat is removed from the respective mandrel. At the pre-treatment station, the plastic cup is subjected to a gas flame or electrical discharge which provides better adherance of the ink to the cup at the subsequent printing station. At the printing station, a printing blanket is brought into contact with each of the cups, to place a decoration on the outer frusto-conical surface thereof, and at the subsequent cure station, the ink is cured by ultraviolet light.
One such machine is sold by the assignee of the present invention, Van Dam Machine Corporation of West Paterson, N.J. under Model 560-COM. Such machine uses a mandrel wheel having eight mandrels spaced equally there around. In order to supply the cups to the feeding assembly, a carousel feeder is provided above the mandrel wheel. Specifically, the carousel feeder includes a plurality of cup holding tubes vertically arranged and spaced about a common circle. Each cup holding tube holds a plurality of stacked frusto-conical cups. Basically, the carousel feeder is rotated so that one stack of cups is supplied to the feeding assembly for the mandrel wheel. After that stack has been completely depleted, the carousel feeder is rotated again to supply another stack of cups to the feeding assembly of the machine, and so on. There is a two-fold problem, however, with the carousel feeder. First, a person must individually feed the cups by hand into each cup holding tube. This is burdensome and time-consuming, and is also difficult, since the cup holding tubes are positioned at a great height above the machine. Secondly, there is a delay in the operation of the machine when a new stack of cups must be fed to the feeding assembly thereof. In other words, before a new stack of cups is fed to the feeding assembly of the machine, the previous stack of cups must be completely depleted and supplied on the mandrel wheel.
Another known cup printing machine is that sold by Van Dam Machine Corporation under Model 560 IR. This machine also includes a mandrel wheel having eight mandrels spaced equally therearound. With this machine, a tray feeding elevator is provided having a plurality of steps in which stacks of horizontally oriented cups can be positioned. As the elevator moves upwardly, each horizontally oriented stack is moved upwardly. The uppermost stack is pushed through a long feed tube to the feeding assembly of the machine. However, this machine also suffers from various disadvantages. For example, the feed tube from the elevator to the feeding assembly must be extremely long and is provided with a substantially 90.degree. bend. Because of the 90.degree. bend, the tray feeding elevator must be much higher than would ordinarily be necessary in order to ensure that the bend is as gradual as possible. In addition, deeply nested, tall narrow cups, could not be used with this machine since they will not travel around the 90.degree. bend of the tube.
Of course, in a machine such as the Model 560-L-120 machine sold by Van Dam Machine Corporation, the bend in the tube need not be as great and the tray feed elevator could be made smaller. However, this is because the mandrel wheel is provided with only six mandrels spaced therearound. Since only six mandrels are used, this machine is limited in other respects.